login
This site is supported by donations to The OEIS Foundation.

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A093712 Repeatedly subtract largest prime from n until either a prime or 1 remains. 0

%I

%S 1,2,3,31,5,51,7,71,72,73,11,111,13,131,132,133,17,171,19,191,192,193,

%T 23,231,232,233,2331,235,29,291,31,311,312,313,3131,315,37,371,372,

%U 373,41,411,43,431,432,433,47,471,472,473,4731,475,53,531,532,533,5331,535

%N Repeatedly subtract largest prime from n until either a prime or 1 remains.

%C The representation as strings of primes is similar to the Zeckendorf expansion, A035514's strings of Fibonacci numbers.

%e a(8) = 71 because 8 = 7 + 1.

%o (PARI) a(n) = {lp = List(); while(n!= 1 && ! isprime(n), p = precprime(n-1); listput(lp, p); n -= p;); listput(lp, n); return (sum(i=1, #lp, 10^(#lp - i)*lp[i]));} \\ _Michel Marcus_, Jun 10 2013

%Y Cf. A000040, A035514.

%K easy,nonn,base

%O 1,2

%A _Michael Joseph Halm_, May 17 2004

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified October 23 08:57 EDT 2019. Contains 328345 sequences. (Running on oeis4.)